Duffel bag



FIG. 1 is a front view of a duffel bag according to the design;

FIG. 2 is a rear view thereof;

FIG. 3 is a left side view thereof;

FIG. 4 is a right side view thereof;

FIG. 5 is a bottom view thereof;

FIG. 6 is a top view thereof; and,

FIG. 7 is a front perspective view thereof.

The broken lines that are shown in FIGS. 1-7 represent stitching which forms part of the claimed design. 

The ornamental design for a duffel bag, as shown and described. 